New Delhi, Aug 12 - Renewing its commitment to bring the Mumbai attackers to justice, the US Wednesday pressed Pakistan to act against the 26/11 perpetrators, including Hafiz Saeed, and underlined that counter-terror cooperation with New Delhi is a 'high priority'.

'People held in Pakistan in connection with the Mumbai attacks should be brought to justice,' US Ambassador to India Timothy J. Roemer told reporters when asked whether the US would press Pakistan to act against Saeed, the alleged mastermind of the Mumbai carnage, amid Islamabad's vacillation over the issue.

Underlining its resolve to bring the architects of the Mumbai terror spree that also killed six Americans to justice, the US envoy said FBI officials would be testifying in the trial of Ajmal Kasab, the lone Mumbai attacker in Indian custody, in Mumbai this week.

Roemer's remarks come soon after Pakistan Supreme Court's decision to postpone indefinitely the petitions challenging the release of Saeed -- the founder of Jamaat-ud-Dawa, a front for the Lashkar-e-Taiba -- that virtually left the Mumbai mastermind free. The court cited the lack of evidence against Saeed while announcing its decision.

Despite India's repeated insistence that it has given enough evidence against Saeed, an India-hating demagogue known for his fiery Friday sermons, Pakistan has been vacillating, asking for more proof.

Roemer, a former member of the House of Representatives who served on the 9/11 commission investigating the Sep 11, 2001 terror attacks on the US, was addressing his maiden press conference as the US envoy to India after he presented his credentials to President Pratibha Patil Tuesday.